com.ql.util.express.instruction.ForInstructionFactory Maven / Gradle / Ivy

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QLExpress is a powerful, lightweight, dynamic language for the Java platform aimed at improving developers’ productivity in different business scenes.
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package com.ql.util.express.instruction;

import java.util.Stack;

import com.ql.util.express.ExpressRunner;
import com.ql.util.express.InstructionSet;
import com.ql.util.express.exception.QLCompileException;
import com.ql.util.express.instruction.detail.InstructionCloseNewArea;
import com.ql.util.express.instruction.detail.InstructionGoTo;
import com.ql.util.express.instruction.detail.InstructionGoToWithCondition;
import com.ql.util.express.instruction.detail.InstructionOpenNewArea;
import com.ql.util.express.parse.ExpressNode;

public class ForInstructionFactory extends InstructionFactory {
    @Override
    public boolean createInstruction(ExpressRunner expressRunner, InstructionSet result,
        Stack forStack, ExpressNode node, boolean isRoot) throws Exception {
        if (node.getChildrenArray().length < 2) {
            throw new QLCompileException("for 操作符至少需要2个操作数 ");
        } else if (node.getChildrenArray().length > 2) {
            throw new QLCompileException("for 操作符最多只有2个操作数 ");
        }
        if (node.getChildrenArray()[0].getChildrenArray() != null
            && node.getChildrenArray()[0].getChildrenArray().length > 3) {
            throw new QLCompileException("循环语句的设置不合适:" + node.getChildrenArray()[0]);
        }
        //生成作用域开始指令
        result.addInstruction(new InstructionOpenNewArea().setLine(node.getLine()));
        forStack.push(new ForRelBreakContinue());

        //生成条件语句部分指令
        ExpressNode conditionNode = node.getChildrenArray()[0];
        int nodePoint = 0;
        //变量定义，判断，自增都存在
        if (conditionNode.getChildrenArray() != null && conditionNode.getChildrenArray().length == 3) {
            int tempPoint = result.getCurrentPoint();
            expressRunner.createInstructionSetPrivate(result, forStack, conditionNode.getChildrenArray()[0], false);
            if (result.getCurrentPoint() > tempPoint) {
                nodePoint = nodePoint + 1;
            }
        }
        //循环的开始的位置
        int loopStartPoint = result.getCurrentPoint() + 1;

        //有条件语句
        InstructionGoToWithCondition conditionInstruction = null;
        if (conditionNode.getChildrenArray() != null
            && (conditionNode.getChildrenArray().length == 1
            || conditionNode.getChildrenArray().length == 2
            || conditionNode.getChildrenArray().length == 3)
        ) {
            expressRunner.createInstructionSetPrivate(result, forStack, conditionNode.getChildrenArray()[nodePoint],
                false);
            //跳转的位置需要根据后续的指令情况决定
            conditionInstruction = new InstructionGoToWithCondition(false, -1, true);
            result.insertInstruction(result.getCurrentPoint() + 1, conditionInstruction.setLine(node.getLine()));
            nodePoint = nodePoint + 1;
        }
        int conditionPoint = result.getCurrentPoint();
        //生成循环体的代码
        expressRunner.createInstructionSetPrivate(result, forStack, node.getChildrenArray()[1], false);

        int selfAddPoint = result.getCurrentPoint() + 1;
        //生成自增代码指令
        if (conditionNode.getChildrenArray() != null && (
            conditionNode.getChildrenArray().length == 2 || conditionNode.getChildrenArray().length == 3
        )) {
            expressRunner.createInstructionSetPrivate(result, forStack, conditionNode.getChildrenArray()[nodePoint],
                false);
        }
        //增加一个无条件跳转
        InstructionGoTo reStartGoto = new InstructionGoTo(loopStartPoint - (result.getCurrentPoint() + 1));
        result.addInstruction(reStartGoto.setLine(node.getLine()));

        //修改条件判断的跳转位置
        if (conditionInstruction != null) {
            conditionInstruction.setOffset(result.getCurrentPoint() - conditionPoint + 1);
        }

        //修改Break和Continue指令的跳转位置,循环出堆
        ForRelBreakContinue rel = forStack.pop();
        for (InstructionGoTo item : rel.breakList) {
            item.setOffset(result.getCurrentPoint() - item.getOffset() + 1);
        }
        for (InstructionGoTo item : rel.continueList) {
            item.setOffset(selfAddPoint - item.getOffset());
        }

        //生成作用域结束指令
        result.addInstruction(new InstructionCloseNewArea().setLine(node.getLine()));

        return false;
    }
}